<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div class="box">
        <ul>
            <li v-for="(item,index) in list" :key="item.id">{{item.num}}<button @click="del(item.id)">删除</button></li>
        </ul>
        <button @click="add">生成</button>
    </div>
    <script src="https://cdn.bootcdn.net/ajax/libs/vue/2.7.14/vue.js"></script>
    <script>
        const box = new Vue({
            el: '.box',
            data: {
                // num: Math.floor(Math.random() * 20)
                list: [
                    // { id: 1, num: Math.floor(Math.random() * 20) },
                    // { id: 2, num: Math.floor(Math.random() * 20) },
                    // { id: 3, num: Math.floor(Math.random() * 20) },
                ]
            },
            methods: {
                add() {
                    this.list.push({
                        id: +new Date(),
                        num: Math.floor(Math.random() * 21)
                    })
                },
                del(id) {
                    this.list = this.list.filter(item => item.id !== id)
                }
            }
        })
    </script>
</body>

</html>